Flip this DIY hourglass over and watch its LEDs fall like sand | Arduino Blog

For centuries, hourglass instruments have been used to keep track of a certain amount of time. But while long superseded by other methods, this project by Ty and Gig Builds takes things full circle, creating an electronic version around WS2812B addressable LEDs.

The frame takes the form of a sort of 2D wooden hourglass, with RGB strips connected to snake from one end to another. An accelerometer reads whether the device is up or down, which passes orientation info to an Arduino Mega. The Mega in turn controls animations, simulating grains of sand as points of light dropping from the top section. As this happens, the bottom half incrementally fills with lit LEDs (as the top becomes dark), and the instrument can be again turned to reverse the process.